The present invention relates to a disk drive, such as a hard disk drive, and a method of controlling the disk drive.
In most cases, a hard disk included in a hard disk drive is provided with a plurality of concentric circular tracks each divided into a plurality of sectors.
To access a disk, a host computer specifies a sector to be accessed by, for example, a logical block address (LBA). A hard disk controller included in a hard disk drive converts the LBA into information specifying a physical sector position on the disk and moves a head to the physical sector position.
The head is moved by the following head moving operation. The hard disk controller converts the LBA into a cylinder head sector parameter (CHS parameter). The hard disk controller specifies a track to be accessed by information, specifying a cylinder and the head, included in the CHS parameter and moves the head to the specified track. This head moving operation is called a seek operation.
The hard disk controller creates an identifier table (ID table) associating identifiers identifying sectors on the specified track with LBAs of the sectors during the seek operation. After the completion of the seek operation, the hard disk controller determines an identifier identifying the sector indicated by the specified LBA with reference to the ID table. The sector identified by the thus determined identifier is located at a position corresponding to the head, and then the sector is accessed.
A recently proposed sequential access system moves the head from track to track without performing the seek operation. The sequential access system repeats an access operation that accesses the sectors of one track sequentially, and then accesses the sectors of another track radially next to the former track. Access systems that move the head from track to track without performing the seek operation includes a spiral track system that uses a disk provided with tracks continuously formed in a spiral and a spiral access system, such as that disclosed in Patent document 1 (Japanese Patent Laid-open No. 9-167457), and that moves the head for reading and writing along a spiral path relative to concentric tracks.